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Discussion Starter · #1 ·
The engine was overheating so i did some troubleshooting on the way. The following results arose:

-With the airconditioning on, the high speed fan kicks in for a short bursts

-Did multimeter voltage measurements on the low speed fan relay connectors:

Connectors 85&86 : Steady 13.73 V
Connectors 30&87 : Slowly Rising up to 10 V.


I think the resistor is 0.22 Ohms multiplied by 30 Amps that would give maximum a 6.6 Voltage drop from the battery's voltage (which mine measured is 14V with the engine on).
If i understand the cicruit schematic correctly, 30 & 87 are fed into the fan

So, the 30 & 87 connector's voltage seems quite reasonable . If there was a fault, i would probably not register a voltage reading at all. What worries me is :

Swapped the relays between low beam and low speed fan. The relay of the low speed fan is powering the lights a-ok......Is this relay supposed to be identical to the low beam relay ? (mine is)

So it must be either temperature sensor or the fan low speed motor.

QUESTIONS:
-Are the 13.73 V in 85&86 connectors reasonable at all?
-If it is the temperature sensor where is it located? (from forum reading i know there are two of them -which do i change?)
-Are there other sensors/parts included in the system ?
-If it is the temperature sensor, why does it not show on the temp gauge? The temp gauge rises quite smoothly....
-What are the chances of a possible wiring problem between ICE and fuse box?

Chris
 

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Well, you made long question, so have a long answer :)

1. 85/86 connectors are relay's coil. When there's a voltage, the relay kicks in. 13 V is reasonable.
2. 30 is power from battery and 87 is routed to the fan. Any voltage reading across these points is (IMO) useless - a motor behaves like resistor.
3., 4., 5, etc:

Story goes approx like that: there is a temperature sensor (I know just one) that sends information into DICE. This box then controlls temperature gauge on dashboard and fan relays (and bunch of other temperature-related stuff, such as amount of injected fuel...). So if you're having normal temperature gauge, the sensor is also fine.

Fan has two speeds with following state-of-the art technology: high speed wire is routed directly into the motor, low speed one is routed via a resistor (mounted on a fan housing) - there is just one motor. Also included are two relays, as you allready know. High speed can be activated through high coolant temperature or pressure in the aircon system.

A very common error is blown resistor. To test it, put a jump wire across terminals 30/78 on relay connector (use a thick wire and don't hold it with bare hands). If nothing happens, it is gone. Resistor is not available as a separate part, but similar ones can be obtained at various places (about 0,2 Ohm and 50 Watt). Removal of the fan without radiator is troublesome, but can be done. Assembly of replacement resistor requires soldering knowledge plus some additional creativity (I put faston connectors on mine and overflood it with solder), don't forget insulation as the area can get wet on rain.
 

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Discussion Starter · #3 ·
Well, you made long question, so have a long answer :)

Story goes approx like that: there is a temperature sensor (I know just one) that sends information into DICE. This box then controlls temperature gauge on dashboard and fan relays (and bunch of other temperature-related stuff, such as amount of injected fuel...). So if you're having normal temperature gauge, the sensor is also fine.
Boris

Thanks on the answer firstly.

When i read the bold stuff, something else hit me : I have seen an increase in fuel consumption: 4 mpg less according to the SID

Another thing that hits me is the following in what regards voltages (i am not questioning, simply wondering:

the 30 & 87 on the high speed circuit register 13.73 V constant even with the engine off, while the same on the low speed register less. If there was no circuit at all would they not register 0 voltage ?

However will try tomorrow the cable thingy (hope i dont burn anything)
 

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Such voltage measurement doesn't make sense. You should measure 30 to ground (and read battery voltage) while 87 to anything is useless information. Wiring on that segment is pretty simple: battery - maxi fuses - relay (#30) - fan motor (via #87).
 

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Discussion Starter · #5 ·
Boris,

Thanks for the info; reviewing the circuit you are right!

30 to ground registers the battery voltage; That however does not preclude i guess the blown resistor :)....

I guess i am off now to find a correct lead for jumping the fans :)
 
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